The home energy management system (HEMS) of the Robotina company, is an all rounded energy optimization solution. It is thus, one of the best things that has hit the energy sphere, with a gross overall improvement ratio as observed by utilizing households and other energy consuming structures. The system rightly qualifies as an appropriately fashioned innovation that is self sufficient and yet effective in transforming a passive energy utilizing household, into a proactive energy utilizing entity.

Although the operation route is rather not so much of a complex one, it still remains an innovation that is regarded as a ground breaker for effective energy optimization. HEMS links to various functioning components like power meters, sensors and other smart devices, while using gathered information on energy generation and consumption, in effecting a reasonable management and optimization schedule- the type that suits the user. All of these ultimately culminates into high levels of energy efficiency, as well as cost minimization.

Consequently, HEMS is able to effect a transition from a passive prosumers state, to a proactive energy prosumers status by the following ways:
• Describing energy consumption tendencies of energy utilizing appliances and systems in the home (as shown below)
• Developing and implementing energy production and consumption regulating strategies- for both the entire household as well as the individual devices.
• Distributing passive and active devices into individual production and consumption frameworks.
• Forming a dedicated algorithm for the evaluation of adopted energy management methods.

Consumption profile
The consumption profile is important because it helps in the improvement of the building management system. In order to map out an energy consumption monitoring and control formulae, there must be a consumption profile that is adhered to. This requires putting additional measured quantities to consideration to show the consumption cycle and the profile tendencies. Load management is used in balancing the load shifting possibilities within HEMS, through a knowledge of profile patterns, as well as user-defined temporal and hardware limitations. HEMS operation requires information on the optimized schedule for all the individual appliances connected to the overall HEMS framework. This is what can be referred to as planning, for the function benefit of the user.

Figure 1:An electric water heater showing energy consumption pattern within HEMS

The diagram above shows the heating pattern of a water heater, whose actions are being regulated by an integrated thermostat. Once temperature falls below required, the heater starts to heat the water again until the temperature rises (as shown in the circled region).

Consequently, the pointed arrow shows the efforts of HEMS in finding a temporal region of water heater conditions. This region would correspond with user defined specifications, device type, energy pricing, amongst others. In situations where energy supply and consumption is affected by the prevailing weather (such as in photovoltaic generation), such instances should have been considered in the HEMS operation planning. For circumstances like this, a weather forecast is important in predicting the functioning of certain connected devices within HEMS.

Figures 2 and 3 below shows energy consumption patterns of electric water heater in two scenarios: without HEMS installation (fig. 2), and with HEMS installation (fig. 3).

As described in figure 2, there is no planning and management implemented. Thus, the water heater functions based on fluctuation differences using minimum and maximum temperatures only. This makes it heat the water for as many times as possible, without an energy saving input.

However, planning and management in figure 3 allows the HEMS system to implement a time slot, while ensuring that the water heater only functions in agreement with predefined criteria such as energy pricing, and other user defined consumption restrictions. In order to ensure the effectiveness of this format, HEMS brings about a delay in the heater operation until a time (t) that occurs within the shifting area. By the schedule implementation, there is no lapse in hot water generation for the times when it is needed.

Figure 2: Electric water heater- without HEMS installed

Figure 3: Electric water heater- with HEMS unit installed